Deployment of filters, proportional gains, and integral gains to comprise a speed controller's compensation equations is well established and this particular invention does not make new proposals in terms of the form or type of equations that execute in the control itself. Automation of “servo tuning” or controller “optimization” is less established, but nonetheless is also an area of significant prior art.
In U.S. Pat. No. 6,198,246, to Yutkowitz, Yutkowitz describes that an optimum value for a speed controller's proportional gain (Kp) could be determined by iteratively adjusting loop shaping filters to find the combination that yields the maximum Kp while maintaining requirements for gain and phase margins (stability margins). The process involves manipulation of the system's open-loop frequency response function to evaluate the stability margins that result at each iteration. A specific set of rules for the automation of such a technique was not described, instead the Yutkowitz outlines an environment that would involve the interaction of a setup technician with the software via a graphical user interface, where the user would be responsible for selecting the optimal values based on immediate feedback from the graphical interface.
In U.S. Pat. No. 6,347,255, to Moser, Moser describes a technique for selecting notch filters to cancel mechanical resonances and enable increased gain. The Moser patent does not offer any guidelines for iterating the filter selection parameters. Rather, it describes only iteration of the proportional gain to match a predetermined template representing a model for approximate system dynamics. Once the proportional gain is determined filter selection is carried out in a single step. The two components of the compensator are determined separately, thus the interaction is not considered and the result will be less than optimal. Another difference is that the selection of proportional gain is based on amplitude of closed loop response rather than the examination of stability margins. Finally it does not offer suggestions of how to represent the concepts and algorithms in terms of object classes.
Accordingly, a need exists for a device, method, and system for quickly and efficiently selecting filters and loop proportional gain for a closed loop system.